Chromable azodyestuffs derived from formaldehyde sulphurous acid and nitrated 1-(azo-naphthol)-2-hydroxy-naphtahlene-4-sulphonic acid and process of making same



- maldehyde sulpliurous which are obtainable by- Patented June 28, 1927.

srarss PATENT mime:

FRITZ STBAUB, BASEL, AND I-IERMANN SCHNEIDER, OF RIEHEN, NEAR BASiEIi,

SWITZERLAND, 'ASSIGNORS TO SOCIETY OF CHEMICAL INDUSTRY IN BASLE, 0F

BASEL, SWITZERLAND, A FIRM.

AND NITRATED ACID AND rnocnss OF MAKING SAME.

N0 Drawing. 'Application'filed 11113 21, 1926; Serial no, 124,097, and

The present invention relates to new chromable azo dyestuffs which are particularly valuable for producing fasttints on the animal fibre. The invention comprises the new dyestufis, the method of making same, and the material dyed with the new dyestufis.

The dyestulis are made by treating with formaldehyde and a bisulfite, or with foracid or a salt thereof, the amino dyestuffs reducing the products which are made by coupling the nitrated diazo compound of the 1-amino-2-oxynaphthalene-4;-sulphonic acid with an unsulphonated naphthol such as a-naphthol or B-naphthol.

The new dyestuffs thus obtained correspond very probably with the general formula N:NVR

in which R stands for a. residue of an unsulphonated naphthol. They are very well suited for dyeing animal fibre with aid of chromium mordant (according to the known processes of mordanting wlth chromium and chroming), for they produce dyeings of prominent properties in respect of fastness. They form blackish powders, which dissolve in water to violet-brown solutions, in dilute caustic soda solution to black and in concentrated sulphuric acid to blue solutions.

Example.

450 parts by weight of the ortho-hydroxyazo-dyestuif obtainable by reducing the product made by coupling the nitrated diazocompound. l-arnino-2-hydroxynaphtha- 285 parts of sodium bisulphite GHRO MABLE AZODYESTUFFS DERIVED FROM FOBMALDEHYDE SULPHU 'ROUS ACID 1- (AZO-NAPHTHOL) 2-HYDROXY-NAPHTHALENE-4-SULPHONIC lenel-sulphonic acid With B-naphthol are dissolved, preferably in theform of the reduction massfreshly obtained, in about 8000' C. containing parts parts of waterat of caustic soda; a mixture of 100 partsjof formaldehyde of 35 per cent strength and liquorot 40 per cent strength are added. After stirring for some time acetic acid of 10 per cent strengtlris added until the intense blue of the solution is changed to violet; salting out and filtration then follow. VJhen dry the new, product is a black powder which dis- 7 solves in water to a violet-brown solution, in dilute caustic soda solution to a black and in concentrated sulphuric acid to a blue solution. In contrast with the parent dyestut'f the new product is soluble in cold water and remains dissolved even after addition of mineral acid to the solution, therefore it may be dyedin a sulphuric acid bath. It corresponds very probably with the formula:

ne I

treatment of the in'swit z erland September 24, 1925;

' new pling products of the nitrated diaZo-derivative of 1 amino-2-oxynaphthalenel-sulphonic acid with B-naphthol, with the reaction product of bisulphite on formaldehyde. 3. As new products the herein described azo dyestufis corresponding very probably with the general formula:

black powders which dissolve in water to violet-brown solutions, in dilute caustic soda solution to black and in concentrated sulphuric acid to blue solutions and which dye wool, when afterchroined, very fast. black shades which are particularly fast to potting.

4. As a new product the herein described new 2120 dyestufi' corresponding Very probably with the formula: 7

which product forms a black powder which dissolves in Water to a violet-brown solution,

in dilute caustic soda solution to a black and in concentrated sulphuricracid to a blue solution, and which dyes wool, when after chromed, a Very fast black shade which is particularly fast to potting.

In witness whereof we have hereuntosigned our names this 10th day of July 1926.

FRITZ STRAURM HERMANN SCHNEIDER. 

